Cutting oil of reduced stray fog

ABSTRACT

A metal working composition having improved low fog properties is disclosed which comprises a major portion of a hydrocarbon oil and a minor amount of an antifog additive selected from polyisobutene, poly-n-butene and mixtures thereof, and having a viscosity average molecular weight ranging from 0.3 to 10 million.

United States Patent 1 1 Altgelt i5 1 CUTTING OIL OF REDUCED STRAY FOG [75] Inventor: Klaus H. Altgelt, San Rafael, Calif.

[73] Assignee: Chevron Research Company, San Francisco. Calif [22] Filed: Nov. 5, I973 [21] Appl. No.: 413.150

FOREIGN PATENTS OR APPLICATIONS 1.099.450 l/l968 United Kingdom i. ISJ/l E 1 Nov. ll, 1975 Primur Ermm'new-Delbert E. Gantz Assistant Emrm'ner-Andrew H. Melz Attorney Agent. or FirmG. F. Mugdehurgcr; C. J Tonkin [57] ABSTRACT A metal working composition having improved low fog properties is disclosed which comprises a major portion of a hydrocarbon oil and a minor amount of an antifog additive selected from polyisobulcne. pol n-butene and mixtures thereof. and having a viscosity average molecular weight ranging from ()3 to ll) million.

l0 Claims. No Drawings CUTTING OIL OF REDUCED STRAY FOG BACKGROUND OF THE INVENTION In most industrial metal cutting operations, a cutting fluid is employed. Cutting fluids act both as a coolant to maintain the temperature of the metal surfaces within a desired range and as a lubricant to lubricate the inner face of the cutting tool and metal. The cooling effect of the cutting fluid adds considerable life to the cutting tools, such as drill bits, etc., and also tends to prevent the warping or distortion of the metal. The lubricating properties, on the other hand, reduces the friction between the cutting tool and the metal, thereby reducing the power requirement of the machinery.

A reoccurring problem associated in the use of cutting oils, particularly hydrocarbon cutting oils, is that of fog generation. During the cutting process, a small amount of cutting oil is thrown off into the surrounding air as micro-sized droplets known as a fog. Workers in the vicinity are exposed to the fog and, unless a protective breathing apparatus is worn, a portion of the fog is inevitably drawn into the workers lungs.

The health hazards associated with fog generation have recently prompted Federal Governmental Agencies (OSHA) to enact stringent fog limitations on grinding and high-speed metal operations using cutting oils. A need, thus, exists for a cutting oil which provides good lubricating and cooling properties, which does not create a large amount of fog during operation of the cutting equipment, and which is relatively inexpensive to use.

It is an object of this invention to provide an improved cutting oil.

It is an additional object of this invention to provide a cutting oil having low fog properties.

It is an additional object of this invention to provide a method for reducing fog generation surrounding metal cutting equipment employing a cutting fluid.

Other and related objects of this invention will become apparent from the following detailed description of the invention and in the claims.

SUMMARY OF THE INVENTION The aforementioned objects and their attendant advantages can be obtained by incorporating into a cutting oil from 0.0001 to 2 weight percent of an antifog additive selected from polyisobutene or poly-n-butene having a viscosity average molecular weight within the range of 0.3 to million.

Although the exact mechanism of the polybutene polymer in reducing the fogging properties of a cutting oil is unknown, it is believed that the polybutene dissipates mechanical energy concentrated at certain parts of the oil surface by converting it into mechanical energy of the polymer molecule and finally into heat. The mechanical energy transferred from the cutting tool to the oil causes the latter to undergo vibrations which break the liquid up into drops. The vibration continues in the drops leading to further disintegration into smaller and smaller droplets. It is believed that the polybutene molecules at the oil surface take a substantial amount of the vibration energy up and thereupon undergo more rapid and more extensive rotation and molecular extension and contraction. In doing so they undergo collisions with numerous oil molecules farther away from the surface. As a result, the mechanical energy is partly transferred to the interior of the bulk liquid and eventuallydissipated as heat. In any event, it has been found that the incorporation of a minor amount of the polybutene in a cutting oil substantially reduces the fogging tendencies of the oil.

DETAILED DESCRIPTION OF THE INVENTION The incorporation of a very small amount of a polyisobutene or poly (normal) butene having a viscosity average molecular weight between 0.3 and I0 million into a cutting oil can reduce the fogging tendencies of the cutting oil by more than and in some instances by more than 99%.

The polybutene polymer which may be employed in the practice of this invention to improve the antifog properties is a polybutene, preferably a polyisobutene. having a viscosity average molecular weight from 0.3 to ID million, preferably from .5 to 5 million, and more preferably from l.l to 3 million. The polymers are commercially available and may be prepared by conventional olefin polymerization techniques such as catalytic polymerization in the presence of aluminum chloride or boron fluoride.

The amount of polybutene polymer sufficient to suppress oil fog within the cutting oil may vary from 0.0001 to 2 weight percent, preferably from 0.001 to 0.1 weight percent, and more preferably from 0.0] to 0.08 weight percent.

The cutting oil of this invention can comprise a mineral oil or synthetic hydrocarbon oil of lubricating viscosity, i.e.. with the viscosity ranging from 50 to 500 SUS at 38C (100F). The oil may be paraffinic, naphthenic, aromatic or mixed base. The oil may be a single refinery cut, or may be a blend oftwo or more oils in the appropriate proportions to give the desired viscosity of the blend. The lubricating oil will represent the major portion of the composition of this invention and will comprise about 90 to 98 weight percent of the composition, and preferably from 90 to 96 weight percent.

In addition to the polybutene antifog agent, other additives may be present within the cutting oil composition of this invention. One additive which may be used is an extreme pressure agent. Exemplary extreme pressure agents include fatty oils and fatty acids, sulfurized fatty oils, sulfurized oils, sulfochlorinated oils, chlorinated oils, organic phosphorus compounds, organic thiophosphates, etc. Since extreme pressure agents are well known to those skilled in the art and are continuously used in this type of service, they need not be described in more detail here. When employed, the extreme pressure agent is used in an amount from 1 to 20 weight percent, and preferably from 5 to 10 weight percent.

Other additives which may be employed include antioxidants such as organic compounds containing sulfur, phosphorus, or nitrogen. rust preventives such as sulfonates, amines, fatty oils, etc., metal deactivators such as complex organic nitrogen and sulfur-containing compounds, emulsifiers such as certain soaps and fats and fatty acids, sulfonic acids, naphthenic acids, etc., odor control agents, pour point depressants, antiseptics, foam inhibitors, oiliness agents, etc.

EXAMPLE 1 This example is presented to demonstrate the effectiveness of the polybutenes of this invention in reducing fog with an exemplary cutting oil. In the test, a sample oil is fed from a reservoir through a thin tubing to the center of a 1 inch diameter wheel driven by an electric motor at 27.000 rpm. The oil is flung to the side within an enclosed chamber and collected in a specially shaped cup which fits over the wheel. Because of the high shear. a small amount of the oil is converted into a stable fog consisting of droplets between 2 and 500 microns in diameter. This fog is driven by a vacuum through a filter where the oil is collected. The weight of the oil on the filter is determined and the ratio of the oil on the filter to the oil in the cup gives the percent of fog generated by the spinning wheel.

The sample cutting oils tested in this example comprise various amounts of several types of polymers incorporated into a cutting oil base. The cutting oil base is comprised of a blend of 2 parts of a solvent-refined. naphthenic lubricating oil having a viscosity of 100 SUS at lF and 1 part of the same type of oil having a viscosity of 360 SUS at I00F. The sample blends are tested in the above fog test with the results displayed in Table 1 below. The description of the polymers employed in each test are also set forth in the table.

TABLE I 2. H10 composition defined in claim 1 wherein said hydrocarbon oil is a paraffinic or mixed base mineral oil.

3. The composition defined in claim I wherein said antifog additive is present in an amount from 0.00l to 0|.

4. The composition defined in claim I wherein an extreme pressure additive is also present.

5. In a process for cutting a metal with a metal cutting tool wherein a cutting oil is contacted with said metal cutting tool and said metal during the operation, and wherein a portion of said cutting oil is displaced into the air surrounding said metal cutting tool as a fog of micronic-sized droplets. the improvement in reducing the amount of said fog which comprises incorporated into said cutting oil, from 0.000] to 2 weight percent of an antifog additive selected from polyisobutene, poly n-butene, or mixtures thereof. having a viscosity average molecular weight ranging from 0.3 to l0 million.

6. The process defined in claim 5 wherein said antifog additive is a polyisobutene having a molecular ADDITIVE EFFECT ON OlL FOG Polymer Additive Increase in Fug As can be seen from the above table, the employment of a high molecular weight polyisobutene reduced the fog of the base oil by more than 90% and in some cases more than 99%. Some of the other polymers such as the polymethacrylate actually increased the percent fog rather than decreasing it.

I claim:

I. A composition of matter having metal working properties comprising a major portion of a hydrocarbon oil having a viscosity of 50 to 500 SUS at l00F and from 0.000l to 2 weight percent of an antilog additive selected from polyisobutene, poly n-butene or mixtures thereof. having a viscosity average molecular weight ranging from 0.3 to million.

weight from 0.3 to l0 million.

7. The composition defined in claim I wherein said polyisobutene, poly-n-butene or mixture thereof has a viscosity average molecular weight ranging from 0.5 to 5 million.

8. The composition defined in claim 1 wherein said anti-fog additive is present in an amount from 0.001 to 0.] weight percent.

9. The process defined in claim 5 wherein said antifog additive is present in an amount from 0.001 to 0.1 weight percent.

10. The process defined in claim 5 wherein said polyisobutene, poly-n-butene or mixture thereof has a viscosity average molecular weight range from 0.5 to 5 million. 

1. A COMPOSITION OF MATTER HAVING METAL WORKING PROPERTIES COMPRISING A MAJOR PORTION OF A HYDROCARBON OIL HAVING A VISCOSITY OF 50 TO 500 SUS AT 100*F AND FROM 0.0001 TO 2 WEIGHT PERCENT OF AN ANTIFOG ADDITIVE SELECTED FROM POLYSIOBUTENE, POLY N-BUTENE OR MIXTURES THEREOF, HAVING A VISCOSITY AVERAGE MOLECULAR WEIGHT RANGING FROM 0.3 TO 10 MILLION.
 2. The composition defined in claim 1 wherein said hydrocarbon oil is a paraffinic or mixed base mineral oil.
 3. The composition defined in claim 1 wherein said antifog additive is present in an amount from 0.001 to 0.1.
 4. The composition defined in claim 1 wherein an extreme pressure additive is also present.
 5. In a process for cutting a metal with a metal cutting tool wherein a cutting oil is contacted with said metal cutting tool and said metal during the operation, and wherein a portion of said cutting oil is displaced into the air surrounding said metal cutting tool as a fog of micronic-sized droplets, the improvement in reducing the amount of said fog which comprises incorporated into said cutting oil, from 0.0001 to 2 weight percent of an antifog additive selected from polyisobutene, poly n-butene, or mixtures thereof, having a viscosity average molecular weight ranging from 0.3 to 10 million.
 6. The process defined in claim 5 wherein said antifog additive is a polyisobutene having a molecular weight from 0.3 to 10 million.
 7. The composition defined in claim 1 wherein said polyisobutene, poly-n-butene or mixture thereof has a viscosity average molecular weight ranging from 0.5 to 5 million.
 8. The composition defined in claim 1 wherein said anti-fog additive is present in an amount from 0.001 to 0.1 weight percent.
 9. The process defined in claim 5 wherEin said anti-fog additive is present in an amount from 0.001 to 0.1 weight percent.
 10. The process defined in claim 5 wherein said polyisobutene, poly-n-butene or mixture thereof has a viscosity average molecular weight range from 0.5 to 5 million. 